Zone leveling of lead magnesium niobate–lead titanate crystals using RF heating

Advances in the Growth and Characterization of Relaxor-PT-Based Ferroelectric Single Crystals

“…Since PMN-PT crystal exhibits the highest piezoelectric response along the <001> orientation, <001>-cut wafers have become highly demanded [16]. Owing to the inevitable axial composition segregation of this solid-solution in the Bridgman process [22,27], highly uniform (001) wafers can only be produced by successful and repeatable <001>-oriented crystal growth. However, since PMN-PT presents the slowest growth rate along the low-index <001> orientation (R <001> < R <110> < R <111> ), the Bridgman growth of bulk PMN-PT crystal along <001> becomes the most challenging.…”

“…Since PMN-PT is a complete solid-solution system, as shown by its high temperature phase diagram, it inevitably exhibits an inhomogeneous composition distribution along crystal boules grown by the Bridgman method [22,27], resulting in the variation of dielectric and piezoelectric properties along the growth direction. Even though the composition variation along the growth direction can be restrained to some degree by applying a higher growth rate and a lower axial temperature gradient across the solid-liquid interface, it can never be eliminated due to the thermodynamic nature of the solid solution system [27]. The composition distribution can be simulated by a well-established equation used for describing the composition segregation behavior in solid solution systems during the normal solidification process [17] …”

“…Theoretically, zone leveling can produce a flat composition distribution except for the initial and last frozen regions (zones). The zone melting growth of PMN-PT crystals was conducted in both RF induction heated and resistance heated furnaces [27,28]. Constant composition at PT = 32% was observed over ~60 mm of total boule length (~80 mm) in a zone-leveled boule compared with the constantly changing composition usually observed in Bridgman grown crystals [27].…”

Domain Structure Evolutions During the Poling Process for [011]‐Oriented PMN–xPT Crystals Across the MPB Region

“…[5][6][7] Due to the successful commercialized production with the Bridgman growth method, the (1Àx)Pb(Mg 1/3 Nb 2/3 ) O 3 -xPbTiO 3 (PMN-xPT) crystal has become one of the most appreciated focus among these ferroelectrics. 2 Efforts to take full advantage of the crystal boules have been made, including improving growth techniques to enhance the longitudinal compositional uniformity 11,12 and extending the useful portion of as-grown boules with optimal piezoelectric properties. Thus, only about 1/3 of the crystal boule is with required electromechanical properties.…”

“…Thus, only about 1/3 of the crystal boule is with required electromechanical properties. 2 Efforts to take full advantage of the crystal boules have been made, including improving growth techniques to enhance the longitudinal compositional uniformity 11,12 and extending the useful portion of as-grown boules with optimal piezoelectric properties. 4 Domain engineering, the technique to design desirable domain configurations, has been developed to study the property anisotropy of the crystals, 4,13 searching for satisfying capacities from various domain configurations (1R/2R/ 4R in rhombohedral phase, 1T/2T/3T in tetragonal phase and 1O/3O/4O in orthorhombic phase) in a wide composition range.…”